Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.
How it was found
First planet found in 2021, by transit and radial velocity (NASA Exoplanet Archive).
Its planets
HD 5278 b — 2.5 times Earth's width, a 'sub-Neptune' — bigger than Earth, smaller than Neptune; its year lasts 14 days; about 670 °C, hotter than boiling water; found in 2021 by transit.
HD 5278 c — 4.5 times Earth's width (estimated from its mass, not measured), Neptune-sized; its year lasts 41 days; about 390 °C, hotter than boiling water; found in 2021 by radial velocity.
NASA Exoplanet Archive, Planetary Systems Composite Parameters (fetched 2026-11-02). Composite values: where a planet's size or mass was not measured, the archive estimates it from the other.
This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program.